Wipe the gunk out of your eyes
Posted Oct 4, 2007 6:43 UTC (Thu) by mingo
In reply to: Wipe the gunk out of your eyes
Parent article: Memory part 2: CPU caches
Yes, we're stuck with the i86 lineage, and we will suffer performance ceilings because of it.
Yes - but this statement ignores the complete economic picture: it's not just the hardware that matters, but the total stack that is in a computing solution. Nobody buys just the raw hardware - the software is an inextractable part of the equation.
So once you take the cost of writing and supporting software into account too, applied to general computing problems that computers are used for, you will realize that today the hardware is not the main limiting factor but humans are. Most software is running a few orders of magnitude slower than it could run on the hardware.
The platform that is slightly slower but offers superior programmability - especially for something as hard to grok for humans as parallelism and/or cache coherency - will continue to be the most economic choice in all mainstream uses of computers. (and will continue to use the resources it earns from the mainstream to chip away on most of the remaining niches)
The trick is to maintain the right balance between programmability of a platform and raw physical performance - and the x86 space has done that pretty well over the years. (combined with the fact that the x86 instruction set has become a de-facto bytecode - so RISC never had a chance even technologically.)
(If only performance mattered then customers would buy hardware by sending complete chip designs and hard disk images to manufacturers, optimized to their business problem, which would then be assembled from scratch. There would be no uniform 'instruction set' per se. We are still decades (or more) away from being able to transform arbitrary, abstract business problems into actual hardware in such a pervasive way, without having any common platform layered between them. The moment you have even just a single persistent layer between the business problem and the hardware (be that layer controlled by the customer or by a manufacturer or by the market), platform thinking takes over and raw performance takes a backseat.)
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